The present invention relates to a recording medium comprising a recording layer, on which a liquid adhesive area and a liquid repulsive area are formed and to which a recording agent used as a solution or a dispersant such as liquid ink is applied so as to form an image on the surface of the recording layer.
CTP plates have received much attention in recent years. The CTP plates are provided to write data designed and prepared for a printing plate on a computer, in the plate as it is. As the CTP plate, a water-free plate, which requires no moisturizing water, has been considered as one of the candidates for the next generation CTP plates because this plate can be used by users without specific skills for printing. Conventionally, as disclosed in Japanese Patent Application Laid-Open (JP-A) No. 7-314934, those recording media having a silicone resin coating layer as the outermost layer have been proposed as the water-free CTP plate materials. This technique uses silicone resin that exhibits a superior releasability against oil ink, and forms an image section by mechanically destroying and removing a coating film of the silicone resin using laser abrasion. However, this method is simple, but debris of the silicon resin is produced and a cleaning unit which removes the debris from the plate is further required.
The inventors of this invention have proposed a plate (recording medium), in JP-A No. 3-178478, that does not require any processes such as developing process and debris process before and after writing process. Moreover, the inventors of this invention have also proposed a recording medium, in Japanese Patent Application No. 11-102405, in which an oil-absorbing binder resin is contained in a recording layer in an attempt to make the base plate less susceptible to contamination. However, it has been found that the recording layer simply containing the oil-absorbing binder resin makes the ink difficult to adhere to an image section, although it makes the base plate less susceptible to ink contamination.
It is an object of this invention is to provide a recording medium that makes a base surface less susceptible to ink contamination, and makes it possible to provide a superior adhesive property of the ink to an image section.
According to this invention, the object is achieved by the respective recording mediums as aspects (1) to (6) of this invention as follows.
(1) The recording medium comprises a recording layer including a first material and a second material independently dispersed in the recording layer. The first material has a property that a backward contact angle to a liquid lowers when the material is heated in a state of being in contact with the liquid, and that the value of the backward contact angle recovers when heated in the air. The second material has a polyorgano-siloxane structure.
(2) The recording medium comprises a recording layer including a first material and a second material independently dispersed in the recording layer, and a binder resin. The first material has a property that a backward contact angle to a liquid lowers when the material is heated in a state of being in contact with the liquid, and that the value of the backward contact angle recovers when heated in the air. The second material has a polyorgano-siloxane structure. The binder resin fixes the first and second material.
(3) The recording medium comprises a recording layer including a first material and a second material independently dispersed in the recording layer, and an oil resistant elastic binder resin. The first material has a property that a backward contact angle to a liquid lowers when the material is heated in a state of being in contact with the liquid, and that the value of the backward contact angle recovers when heated in the air. The second material has a polyorgano-siloxane structure. The oil resistant elastic binder resin fixes the first and second materials.
(4) The recording medium a recording layer including a first material and a second material independently dispersed in the recording layer. The first material has a property that a backward contact angle to a liquid lowers when the material is heated in a state of being in contact with the liquid, and that the value of the backward contact angle recovers when heated in the air. The second material is an oil-state material having a polyorgano-siloxane structure, and the oil-state material is cross-linked after un-cross-linked organo-siloxane is dispersed in the recording layer.
(5) The recording medium comprises a recording layer including a first material and a second material independently dispersed in the recording layer. The first material has a property that a backward contact angle to a liquid lowers when the material is heated in a state of being in contact with the liquid, and that the value of the backward contact angle recovers when heated in the air. The second material has a polyorgano-siloxane structure and is formed of fine particles that are cross-linked to each other after fine particle materials having a preliminarily cross-linked polyorgano-siloxane structure are dispersed in the recording layer.
(6) In the recording medium according to any of the above-mentioned aspects, the first and second materials have a solid content weight ratio in a range of 4/6 to 6/4.
Other objects and features of this invention will become apparent from the following description with reference to the accompanying drawings.